The present invention relates generally to inflators for use in inflatable occupant restraint systems in motor vehicles and, more particularly, to baffle systems for replacing filters used in inflators to remove particulates from combustion gases and to cool the gases.
Installation of inflatable occupant restraint systems, such as airbags, as standard equipment in all new vehicles has intensified the search for smaller, lighter and less expensive restraint systems. Accordingly, since the inflator used in such systems tends to be the heaviest and most expensive component, there is a need for a lighter and less expensive inflator.
A typical inflator includes cylindrical steel or aluminum housing having a diameter and length related to the vehicle application and characteristics of a gas generant propellant contained therein. Inhalation by a vehicle occupant of particulates generated by propellant combustion during airbag activation can be hazardous. Thus, the inflator is generally provided with an internal, more rarely external, filter comprising one or more layers of steel screen of varying mesh and wire diameter. Gas produced upon combustion of the propellant passes through the filter before exiting the inflator. Particulate material, or slag, produced during combustion of the propellant in a conventional system is substantially removed as the gas passes through the filter. In addition, heat from combustion gases is transferred to the material of the filter as the gases flow through the filter. Thus, as well as filtering particulates from the gases, the filter acts to cool the combustion gases prior to dispersal into the airbag.
However, the wire mesh filter assembly increases the weight and expense of the inflator. In addition, due to factors such as spatial constraints within the gas generator/inflator and/or the type of gas generant used, combustion of the gas generant may be incomplete when combustion products exit the combustion chamber, resulting in flaming of the combustion products as the gases exit the combustion chamber and enter the wire mesh filter. The porous structure of the wire mesh filter may be unable to contain the flaming combustion products.